Wallboard panel

ABSTRACT

The instant invention is directed to a wallboard panel which is made from new or recycled paper. The panel comprises a pair of sheet members which are parallel in alignment and a honeycomb core sandwiched between the sheet members. The inner surfaces of the sheet members are coated with an adhesive material and the honeycomb core is impressed into the adhesive layers. The honeycomb core is manufactured by a novel process. The sheet members and honeycomb core can be coated with a phenolic resin and/or a fire retardant material. The wallboard panel can also include insulation and/or fire-retardant material disposed within the hollow honeycomb core.

FIELD OF THE INVENTION

This invention relates generally to the field of building wall structures and more particularly to an improved method of manufacturing an improved wallboard panel for attachment to studs in a wall or ceiling.

BACKGROUND OF THE INVENTION

The most common type of wallboard used for interior wall construction in buildings is gypsum board, also known as drywall. It is commonly available under brand names such as Sheetrock© or Gyproc©. Gypsum drywall comprises a sheet of gypsum with a paper facing and paper backing.

Approximately 2.0 million new homes are constructed annually in the United States, most of these employ gypsum drywall in their construction. The gypsum drywall is used for the interior walls, ceilings, and partitions. It has a surface which is suitable for the reception of finish materials and decorations such as paint. While it is a useful and ubiquitous material in building construction, gypsum drywall is difficult to work with. The weight of the gypsum makes the sheets of drywall unwieldy and difficult to manipulate. In addition to its heavy weight, the drywall is extremely fragile and panels of gypsum drywall can easily split in two if they are mishandled.

The process of installation of the drywall panels requires that they be cut to fit around doors, windows and other openings. This usually results in approximately one pound of waste for every square foot of finished house. This results in an average of nearly one ton of gypsum drywall for each single family home built. A reason for the large amount of waste is that walls and ceilings are easier to tape and spackle and are less likely to develop cracks is they are covered with large pieces of drywall from which the openings are cut. Small pieces of drywall require significantly more time and labor for finishing. Also, the joints between them are susceptible to cracking over time.

Debris from construction, remolding, and demolition activities is estimated to account for approximately 24% of the solid waste that is discarded in the landfills across the United States, a large percentage of which is drywall. This large volume of waste creates serious environmental concerns. The disposal of waste gypsum drywall is problematic. Landfill space which receive the waste drywall is becoming less available and more expensive. A greater concern is the face that in a landfill the moist anaerobic conditions allow bacteria to reduce the sulfate component of the gypsum to hydrogen sulfide gas, carbon dioxide, and water. Hydrogen sulfide gas at low concentrations is noxious and at higher concentrations pose serious health and safety risks. Some landfills have already refused to accept drywall waste because of concerns about the hydrogen sulfide gas.

An alternative to the landfills is incineration. Incineration of drywall causes the sulfate present in the gypsum to be converted to sulfur dioxide gas. Air pollution concerns associated with this makes this alternative undesirable. Another alternative is dumping the waste into the ocean. A study of this dumping was done by the Canadian government. The conclusion of this study was that since the materials present in drywall made with gypsum are naturally present in the ocean environment, this method would be environmentally benign. However, the highly negative public perception of ocean dumping of solid waste materials makes this option undesirable also.

While it is technically feasible to recycle drywall, the high costs of recycling the drywall verses the relatively low costs of the raw gypsum make this practice economically undesirable.

As a result of the grave environmental concerns associated with drywall, there is an urgent need for an alternative building material which can be used in place of gypsum drywall. The material should be able to be used in the same manner as gypsum drywall yet overcome the drawbacks and disposal problems associated with gypsum drywall. There is also a need for a wallboard material which is easier to handle than gypsum drywall, which can be inexpensively produced and which is environmentally friendly.

DESCRIPTION OF THE PRIOR ART

The present invention is directed to an improved wallboard made from an improved wallboard material and manufactured by a new and improved process. The improved wallboard is a plurality of paper sheets having a honeycomb core sandwiched between them and the improved material is recycled paper. The improved process is a novel method of manufacturing the honeycomb core. The resulting wallboard is lightweight yet has a superior tensile strength because of the honeycomb core. There are several examples in the prior art of wall panels incorporating a honeycomb core. These include U.S. Pat. Nos. 5,899,037; 4,0104,143 and 6,253,530. From a manufacturing standpoint, honeycomb materials can be characterized as one of two types, expanded or non-expanded. The expanded types are formed from strips of a flexible material, such as paper or plastic, which are stacked and bonded along staggered joint lines. The structure is secured at the top and bottom surfaces and then the stack is pulled apart to produce the honeycomb structure. The stack can be fixed in its expanded form by immersion into a resin bath, or in the case of thermoplastic materials, the stack can be is heated to fix the cells in their expanded condition.

Another type of honeycomb material is non-expanded honeycomb material. This material consists of discretely formed hexagonal tubes which have been bonded together in a honeycomb formation. Each of the prior art references cited above have honeycomb cores which are fabricated using the expansion process.

SUMMARY OF THE INVENTION

The instant invention is directed to a wallboard panel which is made from new or recycled paper. The panel comprises a pair of sheet members which are parallel in alignment and a honeycomb core sandwiched between the sheet members. The inner surfaces of the sheet members are coated with an adhesive material and the honeycomb core is impressed into the adhesive layers. The honeycomb core is manufactured by a novel process. The sheet members and honeycomb core can be coated with a phenolic resin and/or a fire retardant material. The wallboard panel can also include insulation and/or fire-retardant material disposed within the hollow honeycomb core.

Accordingly, it is an objective of the instant invention to provide a wallboard panel which is lightweight and has a high tensile strength.

It is a further objective of the instant invention to provide a wallboard panel which is constructed from new or recycled paper.

It is yet another objective of the instant invention to provide a new process for the manufacture of a honeycomb core.

It is a still further objective of the invention to provide a wallboard panel which is constructed from biodegradable materials so that disposal thereof will not harm the environment.

It is a still yet further objective of the invention to provide an improved wallboard panel which has superior soundproofing characteristics.

Other objects and advantages of this invention will become apparent from the following description taken in conjunction with any accompanying drawings wherein are set forth, by way of illustration and example, certain embodiments of this invention. Any drawings contained herein constitute a part of this specification and include exemplary embodiments of the present invention and illustrate various objects and features thereof.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a wallboard panel according to a preferred embodiment of the invention in which a surface is shown partially cut away;

FIG. 2 is a cross-sectional view taken along line 2-2 in FIG. 1 which illustrates the wallboard panel of FIG. 1 nailed to a wall stud;

FIG. 3 illustrates indicia on the outer surface of the wallboard of FIG. 1;

FIG. 4 illustrates the honeycomb core in its expanded state;

FIG. 5 is a side view of the paper layers illustrating the spacing of the glue strips;

FIG. 6 illustrates how four rolls of paper are brought together to form the pre-expanded honeycomb core; and

FIG. 7 is view of the rotary knives cutting the sheet of paper into strips.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates a wallboard panel 10 according to a preferred embodiment of the invention in which the wallboard panel 10 is shown partially cutaway for ease of description. The wallboard panel 10 can be utilized in the same manner as standard gypsum drywall and advantageously requires no special tools for installation. The wallboard panel 10 is constructed from facing sheet members 12 and 14 which sandwich a honeycomb core 16 therebetween. As seen in the cross-section view shown in FIG. 2, the facing sheet members 12 and 14 have inner and outer surfaces 12 a, 12 b, 14 a and 14 b respectively. The inner surfaces 12 b and 14 b are adhered to the honeycomb core 16. Use of the honeycomb core 16 produces a wallboard panel 10 which is lightweight and has a tensile strength superior to standard gypsum drywall. The honeycomb core 16 also provides superior noise suppression thereby providing superior soundproofing qualities compared to gypsum drywall.

In a preferred embodiment of the invention the facing sheet members 12 and 14 and the honeycomb core are constructed from recycled paper. These elements can also be constructed from new paper. The resultant product is “environment-friendly” from the manufacturing standpoint as well as with regard to the ultimate disposal of the material.

The paper to be recycled can come from a variety of sources. Waste newspaper can be used as well as any other paper or cellulose material. Also, any fibrous material comprised of cotton, wool, linen or the like can be used. Any suitable process known in the art can be employed to recycle paper products to form the components of the wallboard 10 and the invention is not limited in this regard.

As is known in the art, the used paper products such as newspapers, cardboard, magazines office waste paper, etc., is initially soaked in water to soften them. Soaking the paper makes the beating of the wet paper easier. The paper can be initially cut up to speed up the soaking process. The soaked paper pulp is then beaten into a slurry. Sufficient water is added to the paper during the beating process to create an aqueous mixture which is fairly viscous, yet pourable. The beater should not overly chop the paper, since chopping destroys the long paper fibers needed for strength in the final product. The length of the beating is determined by the type of paper being treated.

Various additives and binders can be added to the aqueous mixture during the beating process. In order to add desirable properties to the finished product, fire-proofing chemicals, insect repellents, etc. are added at this stage. The mixture can also be impregnated with phenolic resin which provides waterproofing and insect resistance, as well as inhibiting the growth of fungus and molds. It is preferable to impregnate the paper with up to about 38% by weight of a resin, normally a water or other solvent-based resin, such as a low-emission, waterborne phenolic resin of the type sold by Georgia-Pacific Resins, Inc. of Decatur, Ga.

Plaster and cement can be added to strengthen the final product. It has been found that a mixture including about 20-50% plaster will produce a textured stone hard material. Use of a plaster-impregnated material to fabricate wallboard in accordance with the invention will produce a product suitable for outdoor use. The slurry is then poured into a mold and compressed to form a mat. The strength of the final product is a function of the degree of pressure applied. Greater pressure generally results in a stronger product. In order to obtain satisfactory strength characteristics, it is preferable to use pressures from about 700 to 2000 pounds per square inch (psi). If binders such as plaster and concrete are used, the compressed slurry must be allowed to harden while under the pressure.

The honeycomb core is formed by combining four layers of paper 34, 36, 38 and 40 having strips of glue 42 at specific locations, in a stacked relation with each layer on top of the previous layer, as illustrated in FIG. 5. The glued portions of each layer are spaced from each other in such a manner that the glued portions of each layer are adhered to the adjacent layer of paper below. The non-adhered portions of the layers permit the combined layers to be pulled apart to form a honeycomb structure. This is illustrated in FIG. 4. Each of the four layers of paper contains a narrow band of glue 42 which extends the entire width of each layer. The glue bands of adjacent layers of paper are offset from each other as illustrated in FIG. 5. In a preferred embodiment layers of paper are removed from from four rolls of paper 44, each roll being four feet wide. Glue is applied in a narrow band to the width of each roll by applicators 46. The bands of glue are spaced apart approximately one inch in a preferred embodiment. The bands of glue in adjacent rolls are offset by one half of the distance between the bands or approximately ½ inch so that adjacent layers of paper can be attached to each other as shown in FIG. 5 thereby forming a honeycomb core. Each layer of paper is passed over a roller 48 after the glue is applied. This roller helps to align the layers of paper into a stacked relationship as shown in FIG. 6. After the four layers of paper are attached to each other they are passed over roller 52 and then through a cutter 54 which cut the four foot wide sheets of paper into a plurality of ⅜ inch wide strips. The cutter 54 comprises an axle 56 onto which a plurality of rotary cutting wheels 58 are rotatably mounted. As the layers of paper pass the cutter the cutting wheels cut the paper into strips approximately ⅜ inch wide.

A ⅜ inch wide strip of four sheets of paper are placed on top of another ⅜ inch wide strip of four sheets of paper such that the bottom sheet of the first or upper group is adhered to the top sheet of the second or lower group. This process forms a honeycomb core material which can be expanded to twice the width of a single group of sheets. The strips or groups of paper are attached on top of each other until an expanded section of honeycomb material up to 12 feet long is formed.

Referring to FIG. 2, it is seen that the inner surfaces 12 b and 14 b of the sheet members are respectively coated with adhesive layers 21 and 23. The adhesive is preferably a one component, solvent free, moisture curing, non-volatile urethane adhesive such as Mor-Ad© M-612, produced by Morton International. Mor-Ad division, of Chicago, Ill. Another suitable adhesive is a two component epoxy resin such as one sold under the brand name Stic-Bond©, available from Stic-Adhesive Products Co. Inc., of Los Angeles, Calif. The adhesive layers 21 and 23 are preferably about 5 mm thick. To assemble the wallboard panel 10, the honeycomb panel 16 is impressed into the adhesive layers 21 and 23. Prior to assembly, the open cells of the honeycomb core 16 can be filled with a desired material, such as a fiberglass insulation or a fire-retardant material. The open cells of the honeycomb adjacent all of the outer peripheral edges of the wallboard panel 10 are preferably filled with a viscous material which will harden as it dries. This prevents fraying of the edges of the wallboard. The finished wallboard is preferably ½ inch thick. However, additional wallboard panels could be formed with different thicknesses conforming to conventional wallboard thicknesses.

Along each longitudinal edge of the wallboard the thickness of the wallboard is reduced to allow for the use of tape and spackle to finish the installed wallboard. Normally the abutting edges of wallboard result in a visible joint therebetwen which must be hidden to produce a finished wall. The joint in normally covered with a tape and spackling compound. To allow for the tape and spackle to be placed on the wall without increasing the overall thickness of wall, the thickness of conventional wallboard adjacent these edges is reduced. Accordingly, the thickness along the longitudinal edges of the wallboard of the instant invention will also be reduced.

In use, the wallboard panel 10 is attached to adjoining studs in a wall or joists in a ceiling using an attachment means such as nails or screws. In order to provide a stable anchor for the attachment means a portion of the honeycomb cells 19 can be formed with reinforcing material. As can be seen in FIG. 2, the honeycomb core includes a solid cell 25. The solid cell 25 can be formed by filling hollow cells 19 with a suitable viscous material which will harden as it dries. The solid cell 25 is preferably comprised of a material having a sufficient hardness to hold a nail, or other attachment element, in place, but not so hard as to require pre-drilling of the cell prior to penetration by the nail. FIG. 2 illustrates the wallboard panel 10 attached to a wall stud 50 by a nail 60 which penetrates the solid cell 25.

The solid cells 25 are arranged in a regular pattern within the honeycomb core 16. The solid cells 25 are preferably arranged in vertical and horizontal lines to facilitate attachment of the wallboard 10 to the wall studs 50. The frequency of placement of the solid cells 25 within the honeycomb core can be varied depending on the particular application. As shown in FIG. 3, the outer surfaces 12 a and 14 a are marked with indicia 30 illustrating the location of the solid cells 25 within the wallboard panel 10 to enable someone installing the wallboard to readily located the solid cells 25 during the installation process.

The wallboard panel 10 can be manufactured in various sizes depending on application requirements. The wallboard preferably has a standard depth and the width and length can have any desired dimensions. For example, the width of the wallboard panel 10 can be a standard 4 feet and teh lengths can be in multiples of one foot. Also, papermaking techniques may be used to make the panels in a continuous running length by pouring the slurry onto a moving weir screen wire to a particular depth and delivering the wet material to pressure rolls for compaction and drying, the continuous batt goes through punching rolls which may have a pattern of punches. The areas not punched contain the solid material. Various materials may be added to the punched batt to fill other apertures. Continuous sheets of paper are delivered to both sides of the batt with adhesives applied to the batt or the sheets. The complete panel is compressed again to set the adhesives, then the continuous panel is delivered to a cutter for sizing.

All patents and publications mentioned in this specification are indicative of the levels of those skilled in the art to which the invention pertains. All patents and publications are herein incorporated by reference to the same extent as if each individual publication was specifically and individually indicated to be incorporated by reference.

It is to be understood that while a certain form of the invention is illustrated, it is not to be limited to the specific form or arrangement herein described and shown. It will be apparent to those skilled in the art that various changes may be made without departing from the scope of the invention and the invention is not to be considered limited to what is shown and described in the specification and any drawings/figures included herein.

One skilled in the art will readily appreciate that the present invention is well adapted to carry out the objectives and obtain the ends and advantages mentioned, as well as those inherent therein. The embodiments, methods, procedures and techniques described herein are presently representative of the preferred embodiments, are intended to be exemplary and are not intended as limitations on the scope. Changes therein and other uses will occur to those skilled in the art which are encompassed within the spirit of the invention and are defined by the scope of the appended claims. Although the invention has been described in connection with specific preferred embodiments, it should be understood that the invention as claimed should not be unduly limited to such specific embodiments. Indeed, various modifications of the described modes for carrying out the invention which are obvious to those skilled in the art are intended to be within the scope of the following claims. 

1. A process for forming a honeycomb structure comprising: continuously removing sheets of paper from individual rolls of paper; applying a plurality of bands of glue to one side of each sheet of paper; each band of glue being relatively short compared to the length of the roll of paper and extending substantially the entire width of the sheet of paper; spacing the bands of glue an equal distance from each other; arranging the sheets of paper in a stacked relationship on top of each other; the bands of glue on adjacent sheets being spaced apart in a staggered relationship such that the bands of glue on one sheet are spaced midway between the bands of glue on the adjacent sheet; cutting the sheets of paper into a plurality of strips; attaching the strips in a stacked relationship whereby a plurality of stacked strips forms a section which can be expanded; expanding the strips to form a honeycomb structure.
 2. A process for forming a wallboard panel comprising: forming a pair of rigid sheet members from paper; aligning said sheet members in parallel and in spaced relationship to each other; forming a honeycomb core by the process of claim 1; and attaching the honeycomb core in between said pair of rigid sheet members.
 3. The process of claim 2, further including coating the inner surfaces of each of said sheet members with an adhesive; and impressing said honeycomb core into said adhesive layers.
 4. The process of claim 2, further including filling a plurality of cells of said honeycomb core with a solid material.
 5. The process of claim 2, further including impregnating said honeycomb core with a phenolic resin.
 6. The process of claim 2, further including impregnating said rigid sheet members with a phenolic resin.
 7. The process of claim 2, further including impregnating said rigid sheet members with plaster.
 8. The process of claim 2, further including filing a plurality of cells of said honeycomb core with an insulating material.
 9. The process of claim 2, further including filing a plurality of cells of said honeycomb core with a fire retardant material.
 10. The process of claim 4, wherein said plurality of cells of said honeycomb core comprise the cells immediately adjacent the peripheral edges of said wallboard panel.
 11. The process of claim 2, wherein the thickness of said wallboard panel adjacent the longitudinal edges is reduced. 